1. Field of the Invention
The current invention relates to gas turbines. More specifically, the current invention relates to an apparatus and method for cooling the rotating blades of a gas turbine.
In the turbine section of a gas turbine, the rotor is comprised of a series of disks to which blades are affixed. Hot gas from the combustion section flows over the blades, thereby imparting rotating power to the rotor shaft. In order to provide maximum power output from the gas turbine, it is desirable to operate with gas temperatures as high as possible. However, operation at high gas temperatures requires cooling the blades. This is so because the strength of the material from which the blades are formed decreases as its temperature increases. Typically, blade cooling is accomplished by flowing air, bled from the compressor section, through the blades. Although this cooling air eventually enters the hot gas flowing through the turbine section, little useful work is obtained from the cooling air, since it was not subject to heat up in the combustion section. Thus, to achieve high efficiency, it is crucial that the use of cooling air be kept to a minimum. The current invention discloses an apparatus and method for cooling the blades using a minimum of cooling air.